Brock Lesnar has kissing disease and cannot fight

​Brock Lesnar has pulled out of his already-postponed fight against Shane Carwin at UFC 108 because he's still too sick to train, according to Heavy.com.

Word out of the camp initially was that the illness was H1N1 flu. This sounded plausible, as the swine flu has swept through Minnesota to the point where physicians are not even testing for it anymore, because it's assumed you have it.

But Heavy.com reports that the illness is now believed to be mononucleosis.

Lesnar has battled an undisclosed illness for the past month that forced him to withdraw from a scheduled title defense against Carwin at UFC 106. Heavy.com has been informed that the disease is actually mononucleosis, commonly referred to as "the kissing disease." The bout was rescheduled for UFC 108, but Heavy.com learned earlier this week that Lesnar has not recovered from the illness and cannot train at even a moderate pace without quickly becoming exhausted.

Mononucleosis has a set of common symptoms that are usually presented in the individual with the disease. The classical symptoms are a sore throat, fever, fatigue, weight loss, malaise, pharyngeal inflammation petechiae and loss of appetite, common signs include lymphadenopathy (enlarged lymph nodes), splenomegaly (enlarged spleen), hepatitis (refers to inflammatory cells in the liver) and hemolysis (the bursting of red blood cells).

Although it's called "the kissing disease," there are many other ways to get mono, including sharing drinking glasses. Lesnar is married to Rena Mero, also known as former WWE diva Sable, with whom he recently had a child.